The present invention relates to a method for damping vibration of a substrate and a composition therefor, and especially, although not exclusively to such a method and composition suitable for use in the automotive industry.
As the automobile has evolved, consumers have become continually more sophisticated and demanding. As such, they require many amenities, above and beyond excellent functionality For example, in luxury automobiles especially, the consumer expects a quiet ride. This feature is of such importance that automobile manufacturers frequently spend millions of dollars on advertising campaigns inundating the media with what a smooth, quiet and plush ride their particular automobiles have.
As such, the automotive industry, as well as the aerospace industry, railway the industries, and the truck and bus industry, have dedicated considerable research and development money to improving on a vehicle's noise, vibration and harshness (NVH) characteristics.
Many means have been attempted in order to solve the problem of vibration in a vehicle. One previous method of damping vibration included the placement of moldings and/or pads in appropriate areas. However, several drawbacks existed to this method in that the moldings and/or pads had to be very precisely precut in order to fit properly. Further, they required time consuming assembly to properly and securely attach the moldings/pads to the respective areas. Due to these drawbacks, the moldings and/or pads were nearly cost prohibitive in many cases.
Another solution was to spray epoxy or water born plastisols in liquid form onto (for example, in the automotive industry) a body in white. These sound damping compositions were sprayed wet and remained wet until they were cured. However, curing the plastisol on the body in white required heating. This resulted in several drawbacks, a few of which are that the plastisol composition would drip off and could contaminate the paint and/or E-coat system. Further, this composition could only go on the automotive body at a particular point in the assembly process, namely relatively soon before the body was to be put in the oven for baking (since the plastisol required heat for curing).
Accordingly, an object of the present invention is to provide a new and improved method for damping vibration of a substrate which does not require heating or other specialized process steps. It is a further object of the present invention to provide such a method which is simple and cost effective. It is yet a further object of the present invention to provide such a method which requires very little time in the assembly process and advantageously will not contaminate the vehicle paint or E-coat system. Still further, it is an object of the present invention to provide such a method which may be used at any point in the assembly process, eg. at the metal stamping stage up to and including the body in white stage, and either before or after the application of primer to the body in white.
It is also an object of the present invention to provide a composition which will damp vibration of a substrate, which composition advantageously cures substantially instantaneously in an ambient environment. Yet another object of the present invention is to provide such a composition which does not substantially release volatile organic materials.